The present invention relates to a method of cooling an eddy current brake or power absorption unit by means of a coolant, and also to an eddy current power absorption unit that utilizes such method.
An eddy current power absorption unit (ECPAL) is used to investigate power plants. In use, power delivered by a power plant is converted into heat by means of eddy currents inside the absorption unit. As a result of the eddy currents, the total absorption unit is heated and care must be taken to remove the heat so created.
Existing designs of ECPAUs generally have the disadvantage that their application is limited because at continuous high load the heat created cannot be carried away. As a result of poor heat transfer caused by the shape of the cooling channels and also by the predominantly uneven flow velocity of the coolant in these channels, temperature differentials of significant magnitude occur between the inner wall of the absorption unit facing the rotor and the outer wall thereof. Often these elevated temperatures plastically deform the coolant carrying components. This may result in seizure of the ECPAU or, the elevated temperature as a result of deformation may, after a given time, reach the region of the bearings and may exceed permissible temperatures at those locations. As a result of repeated plastic deformation at relatively high loads cracks often appear in the highly heated zones after relatively short service life. This causes leakage of the coolant into the inner cavity of the unit which renders the unit useless.